Generally, an electronic device (e.g. a power supply apparatus or a server) has a casing assembly for accommodating and protecting a circuit board and electronic components. For combining two casing of the casing assembly together, plural screws are used to connect the two casing with each other. By sequentially tightening plural screws into predetermined screw holes of the two casings, the two casings can be securely combined together. As known, the process of assembling the conventional casing assembly is complicated and time-consuming, and the fabricating cost is high. Moreover, in case that the electronic components within the casing assembly need be repaired, the process of disassembling the casing assembly is also complicated and time-consuming.
FIG. 1 is a schematic cross-sectional view illustrating a portion of a conventional casing assembly. As shown in FIG. 1, the casing assembly 1 comprises a first casing 11 and a second casing 12. The first casing 11 comprises a first lateral plate 111 and a slot 112. The slot 112 is formed in the first lateral plate 111. The second casing 12 comprises a second lateral pate 121 and a hook 122. After the hook 122 of the second casing 12 is penetrated through the slot 112 of the first casing 11, the first casing 11 and the second casing 12 are combined together, so that the casing assembly 1 is fabricated. However, the way of combining the first casing 11 and the second casing 12 by the engagement between the hook 122 and the slot 112 still has some drawbacks. For example, the engagement between the hook 122 and the slot 112 can only limit the horizontal movement of the first casing 11 and the second casing 12 along the normal line direction of the first lateral plate 111 and the second lateral pate 121 (i.e. the direction A as shown in FIG. 1). For limiting the horizontal movement of the first casing 11 and the second casing 12 along other two directions, the first casing 11 and the second casing 12 should be connected with each other through screws (not shown). Moreover, since only a single side of the hook 122 is connected with the second casing 12, the hook 122 cannot be securely fixed on the second casing 12. In other words, the hook 122 is readily suffered from deformation. Moreover, as shown in FIG. 1, the junction between the hook 122 and the slot 112 of the casing assembly 1 is very thick. For example, the thickness of the junction between the hook 122 and the slot 112 is about three times the thickness of the hook 122. After the casing assembly 1 is fabricated, the layout space for accommodating circuit board 13 and other electronic components (not shown) is restricted by the thickness of the junction between the hook 122 and the slot 112. For example, the circuit board 13 is usually equipped with a notch corresponding to the junction between the hook 122 and the slot 112. Due to the notch, the circuit board 13 is not in direct contact with the casing assembly 1. Alternatively, an insulating plate (not shown) is additionally arranged between the electronic components and the first lateral plate 111 (and the second lateral pate 121) in order to maintain electrical safety.
From the above discussions, a large number of screws are required to securely combine the first casing 11 and the second casing 12 of the conventional casing assembly 1 together. Consequently, the processes of assembling and maintaining the casing assembly 1 are time-consuming and troublesome. Moreover, the hook 122 of the casing assembly 1 is easily suffered from deformation. Moreover, the layout space of the conventional casing assembly 1 is restricted by the thickness of the junction between the hook 122 and the slot 112. Consequently, it is difficult to minimize the electronic device.
Therefore, there is a need of providing a casing assembly in order to eliminate the above drawbacks.